A rotary printing machine of the type in which a plurality of printing stations are sequentially passed by a web of paper, and which, additionally, has a mechanism to adjust the length of the path of the web of paper between sequential printing stations, is described in Swiss Pat. No. 521,232. In this known machine, the web of substrate is carried over register rollers positioned between neighboring printing stations. The register rollers permit compensation for variations in distance traveled by any specific area of the web between the printing stations in order to maintain register. The compensating rollers, thus, permit compensation for different paths of the web within the various printing stations. Separate guide rollers are used in order to generate the required web tension. The reference is silent, however, regarding the means and ways in which the deflection and web tensioning rollers are to be controlled or adjusted.